Limited-slip differential for a motor vehicle and motor vehicle

Abstract

The invention relates to a limited-slip differential (10) for a motor vehicle, comprising a differential housing (12) rotatable about an axis of rotation and enclosing a receiving chamber (14), two output gears (16) rotatable relative to each other about the axis of rotation, at least one compensating gear arranged in the receiving chamber (14) which is rotatably held on the differential housing (12) by means of a compensating bolt (17) attached to the differential housing (12) about a compensating pivot axis fixed to the differential housing (12) and which rests against each of the output gears (16), and a differential lock (18) comprising a multi-plate clutch pack (20), wherein the differential housing (12) has at least one first oil supply channel (34) with an inlet opening (38) and an outlet opening (40) by means of which oil (32) can be supplied to the multi-plate clutch pack (20), and at least one second oil supply channel (36) by means of which oil (32) can be led into the reception room (14).

Description

[0001] The invention relates to a locking differential for a motor vehicle and a motor vehicle.

[0002] From EP 2 574 827 B1, a clutch assembly for a motor vehicle is known for transmitting drive power from the motor vehicle to a wheel of an axle with a switchable clutch device, capable of transmitting drive power from a drive element on the drive side with respect to the clutch device to a drive element on the output side with respect to the clutch device. An oil supply device for clutch lubrication is provided, which supplies oil from an oil circuit servicing the clutch device depending on the operating conditions. The clutch assembly is mounted in a housing that forms a clutch chamber for receiving the clutch device. Furthermore, a draining device is provided, which drains oil from the clutch chamber when the oil supply device is not pumping.

[0003] Furthermore, DE 1 123 214 B discloses a differential, particularly for motor vehicles, in which the axle shaft bevel gears, located coaxially to the driven differential, are each connected to one of the axle shafts. The differential has slip clutches arranged between the differential housing and the axle shafts. These slip clutches are located in a cylindrical housing connected to the differential and contain a pack of clutch plates. These plates are pressed together under preload by springs extending from the clutch plate pack and are alternately connected to the cylindrical housing and the axle shafts of the differential. The oil level in the axle housing is slightly lower than the lowest point on the outside of the housing.Therefore, a sheet metal ring is press-fitted to the outside of the housing near its inner end. This ring contains outward-facing, triangularly shaped vanes, formed as a single piece with the ring, which are spaced at intervals around the circumference. Openings serving as oil channels are located in the housing wall below each vane, near the point where the vane joins the ring's circumference. When the axle drive unit rotates, the oil vanes dip into an oil sump located between the axle housing and the housing.

[0004] US Patent 6,436,002 B1 discloses a differential housing comprising a bevel gear differential mechanism, a differential-limiting main clutch and pilot clutch, and a cam mechanism for increasing the engagement force of the pilot clutch, which is transmitted via a transmission element to actuate the main clutch. The vehicle axles inserted into the differential housings are connected to torque-delivery side gears, which are secured against falling out by retaining rings, and to a pressure block that fills the space between. The retaining rings and the pressure block are installed from the outside through openings in the differential housing and the transmission element.

[0005] Furthermore, a conical coupling is known from JP 2002 / 070 890 A, in which a pair of coupling elements with conical surfaces on opposite planes are attracted by an electromagnet in order to be coupled.

[0006] Furthermore, DE 10 2019 105 053 A1 discloses an oil-lubricated limited-slip differential for a motor vehicle comprising a limited-slip differential housing, a limited-slip differential basket rotatably mounted relative to the limited-slip differential housing, a first output shaft, and a second output shaft, wherein the first and second output shafts are rotatably mounted relative to the limited-slip differential basket and are kinematically coupled to each other by a limited-slip differential gear set. A friction clutch is provided for selectively connecting the first output shaft to the limited-slip differential basket. At least one fixed oil supply device is provided in the limited-slip differential housing.Furthermore, the locking differential basket has at least one first and at least one second oil supply recess, so that oil can be supplied to the locking differential gear set by the oil supply device through the first oil supply recess and that oil can be supplied to the friction clutch by the oil supply device through the second oil supply recess.

[0007] The object of the present invention is to provide a solution which enables particularly efficient and reliable cooling of a multi-plate clutch of a particularly compact limited-slip differential.

[0008] This problem is solved according to the invention by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims.

[0009] The invention relates to a limited-slip differential for a motor vehicle. A limited-slip differential is a differential gear frequently used in motor vehicles. If one wheel of the motor vehicle spins, the limited-slip differential transmits a greater amount of torque to the other wheel so that the driving force is not limited by the low traction of the spinning wheel. The limited-slip differential in this case is a differential gear with a differential lock. The differential gear, which can also be called a differential transmission, is a planetary gear transmission with one input and two outputs. The differential gear is therefore a distribution transmission. The differential gear is designed to distribute torque supplied by the motor vehicle's engine between the two driven wheels of the motor vehicle. The differential gear is thus an axle differential.

[0010] A differential lock allows torque to be redirected from the faster-rotating output shaft to the slower-rotating one. In other words, the faster output shaft can be slowed down to benefit the slower one. In this case, the locking differential comprises a driveable differential housing that rotates around a pivot axis and encloses a receiving chamber. This differential housing is a differential carrier of the differential gear. Furthermore, the locking differential includes two output gears that rotate relative to each other around the pivot axis. These gears are located within the receiving chamber and are rotatable relative to the differential housing. The respective output gears can, for example, be conical in shape. Thus, the respective output gears can be considered output cones.Each of the output gears is designed to be rotationally fixed to one of the vehicle's wheels, thus enabling each output gear to drive one of the vehicle's wheels. Furthermore, the limited-slip differential comprises at least one compensating gear located in the receiving space, which is rotatably held on the differential housing about a compensating axis that is fixed relative to the differential housing by means of a compensating bolt attached to the differential housing. In other words, the compensating bolt is fixed in its longitudinal direction relative to the differential housing. Therefore, if the differential housing rotates about the axis of rotation, the compensating bolt rotates with the differential housing.At least one compensating gear is mounted on the compensating bolt, thereby holding the compensating gear to the differential housing and allowing it to rotate relative to the differential housing about the compensating axis defined by the compensating bolt. The compensating gear bears against each of the output gears and is designed to transmit a rotational movement of one output gear to another or to compensate for a relative rotation of the output gears to each other.

[0011] The differential housing thus serves as a carrier for at least one differential gear. The differential gear is therefore a planetary gear of the differential transmission. It is possible for the locking differential to comprise several differential gears arranged within the housing, each of which is rotatable relative to the differential housing about its own axis of rotation, defined by a corresponding compensating pin. Each differential gear is designed to engage with both output gears in order to transmit a rotational movement of one output gear to the other or to compensate for a relative rotation of the output gears about the axis of rotation.

[0012] The differential lock of the limited-slip differential comprises a multi-plate clutch pack. The differential lock is designed to be adjustable between a locked state, in which the first of the output gears is rotationally fixed to the differential housing, and a disengaged state, in which the multi-plate clutch pack allows relative rotation of the first output gear with respect to the differential housing. The differential lock is therefore designed as a multi-plate clutch. This multi-plate clutch is a torque-dependent differential lock. The multi-plate clutch pack enables a positive connection between the differential housing and the outputs.

[0013] In the limited-slip differential, the clutch pack and an actuating device for adjusting the clutch pack's state are arranged on axially opposite sides of the compensating bolt, each radially overlapping one of the differential gears. The clutch pack is fluidly separated from the receiving space by means of a clutch pack end plate. The actuating device allows the clutch pack to be adjusted between the locked and unlocked states. The axial direction is parallel to the longitudinal direction of rotation of the differential housing or the output gears. Thus, the clutch pack and its associated actuating device are arranged on axially opposite sides of the at least one compensating bolt.Furthermore, the clutch pack and the actuating device are arranged such that they each radially overlap one of the differential gears, at least partially. The limited-slip differential thus has a particularly short axial extension. It is therefore provided that the clutch pack radially overlaps one of the differential gears, at least partially, and the actuating device radially overlaps the second differential gear, at least partially. Because the actuating device and the clutch pack are arranged on axially opposite sides of the at least one compensating bolt, the clutch pack end plate is positioned facing the compensating bolt in the axial direction. This means that the clutch pack is closed off by the clutch pack end plate on the side of the clutch pack facing the compensating bolt in the axial direction.The end plate of the clutch pack is designed to seal the clutch compartment of the limited-slip differential, in which the clutch pack is housed, at least against liquids, and in particular against fluids. This prevents any fluid from flowing directly from the clutch compartment into the housing, in which the differential gears and the output gears are located. Specifically, it is provided that both the clutch pack and the at least one differential gear, or the output gears, are cooled by a coolant, in this case oil. For this purpose, oil is supplied to both the clutch pack and the housing. The oil can also be used to lubricate the drive gears and the at least one differential gear.

[0014] The differential housing has at least one first oil supply channel with an inlet and an outlet, through which oil can be supplied to the clutch pack. Furthermore, the differential housing has at least one second oil supply channel through which oil can be supplied to the receiving chamber. Thus, the differential housing is provided with two oil supply channels that are at least partially separate from each other: the first oil supply channel and the second oil supply channel. This ensures that oil can be supplied to both the clutch pack and the receiving chamber of the differential housing via the respective oil supply channels. This ensures reliable cooling and lubrication of the clutch pack, the output gears, and the at least one differential gear.

[0015] It is further stipulated that the limited-slip differential is designed such that, in a first section of a circumferentially extending oil path, the oil is guided radially inwards through the differential housing. In a second section of the oil path, which follows the first circumferentially, the oil is guided radially outwards between axially adjacent lamellae. In the second section of the oil path, the oil flows circumferentially and axially between adjacent lamellae. In the second section, the radial height of the lamellae increases with increasing circumferential distance from the first section. This radial design of the lamellae, combined with the centrifugal forces acting on the oil, assists the oil flowing circumferentially through the oil path.The centrifugal forces acting on the oil cause it to be conveyed or accelerated circumferentially in the second section of the oil path. A drain channel can be connected to this second section, through which the oil must flow so that it can flow out of the differential housing.

[0016] In a possible further development of the invention, an edge limiting the inlet opening of the first oil supply channel rearward in the direction of rotation of the differential housing around the axis of rotation is formed with an angle tapering to a sharp point in the cross-section perpendicular to the axial direction, whereby oil from an oil jet directed towards the inlet opening can be scooped into the first oil supply channel by means of this edge. In other words, the inlet opening of the first oil supply channel is bounded rearward by a sharply tapered edge with respect to the direction of rotation in which the differential housing rotates around the axis of rotation during operation, whereby the oil jet directed towards this inlet opening can be skimmed off by means of this rearward edge.This design, with its rear, tapered edge that defines the inlet opening of the first oil supply channel, ensures the reliable delivery of oil from the oil jet into the first oil supply channel. The inlet opening of the first oil supply channel is thus defined at the rear by a sharp edge, which cuts the oil jet directed towards the inlet opening. This ensures that oil is reliably introduced into the first oil supply channel and prevents it from flowing out through the inlet opening.

[0017] In a further possible embodiment of the invention, an edge defining the inlet opening of the first oil supply channel in the direction of rotation of the differential housing about the axis of rotation is provided by a plate-shaped planing element or a scoop-shaped blade element attached to the differential housing. The planing element can be sharp and thin, similar to a razor or razor blade. It is possible for the planing element to be made of a metallic material. In particular, the planing element is a razor or razor blade. It is specifically provided that the planing element does not project radially outwards beyond any area of ​​the differential housing surrounding the planing element and thus is flush with the differential housing. For this purpose, the planing element can be arranged in a recess of the differential housing.The particularly sharp edge provided by the blade element, which defines the rear boundary of the inlet opening, allows for efficient blade removal of oil from an oil jet directed at the inlet opening, thus ensuring reliable delivery to the first oil supply channel. This edge, defined by the blade element, can have a freely selectable shape. For example, the edge can be straight or curved radially. The blade element can extend radially beyond a surrounding area of ​​the differential housing. The blade element can also feature a radially outward curvature, enabling it to scoop a particularly large amount of oil from the oil jet directed at the inlet opening into the first oil supply channel. The blade element can, for example, be bonded to the differential housing.

[0018] In a further possible embodiment of the invention, the lamellar assembly has a distribution channel formed by recesses, in particular grooves, in several lamellae of the lamellar assembly. The distribution channel extends at least partially in the axial direction, allowing oil flowing to the lamellar assembly to be guided and / or distributed axially by means of the distribution channel. The distribution channel is particularly located on the outer surface of the lamellar assembly. The distribution channel can extend parallel or obliquely to the axial direction. The distribution channel allows oil flowing into the lamellar space to be distributed particularly well between the lamellae or to be guided to all lamellae, thus ensuring that a particularly large number of the lamellae of the lamellar assembly are cooled and lubricated effectively.

[0019] In a further possible embodiment of the invention, the outlet opening opens into the lamellar chamber in which the clutch pack is arranged. In this embodiment, a first edge of the differential housing, which defines the outlet opening towards the compensating bolt, has a greater axial distance to the compensating bolt than an edge of the differential housing defining the inlet opening towards the compensating bolt. Alternatively or additionally, a second edge defining the outlet opening and located axially opposite the first edge has a greater axial distance to the compensating bolt than an edge of the differential housing defining the inlet opening on the side facing away from the compensating bolt. This directs oil flowing in the first oil supply channel axially towards the end disk of the clutch pack.The end plate of the lamellar pack defines the axial boundary of the lamellar pack on the side facing the compensating bolt. The described design of the edge and the outlet opening, in relation to the edges of the inlet openings of the first oil supply channel, results in the first oil supply channel extending axially away from the compensating bolt, from the radially outer inlet opening to the radially inner outlet opening. In other words, the inlet opening of the first oil supply channel is located axially closer to the compensating bolt than the outlet opening of the first oil supply channel. Thus, oil can be guided into the lamellar space via the first oil supply channel in a direction extending axially away from the compensating bolt and in a radial direction from the outside to the inside.As a result, the clutch pack arranged in the clutch chamber can be subjected to an oblique oil flow. This significantly reduces the risk of oil being thrown radially away from the clutch pack due to rotation of the clutch pack, which is fixed to the differential housing. This ensures reliable lubrication of the clutch pack with oil.

[0020] In this context, it can be specifically designed that the lamellar space forms a radial undercut towards the outlet opening, allowing the oil to collect in the undercut. Specifically, an oil pool forms in the undercut, with the radial height of the undercut determining the amount of oil that can accumulate. An oil level within this pool extends axially and in the direction of rotation. This undercut causes oil flung radially from the lamellar assembly due to its rotation around the axis of rotation to collect in the undercut, thus forming a kind of oil sump. The oil collected in the undercut can then be used to lubricate and cool the lamellar assembly.In particular, it is intended that at least one lamella, especially several individual lamellae, protrude into the oil sump in the undercut, which allows these lamellae to be cooled particularly well by means of the oil.

[0021] In this context, it can be specifically designed that the undercut deepens radially with increasing axial distance from an outlet opening. This means that the greater the axial distance of a section of the undercut from the outlet opening, the further the undercut projects radially beyond the outlet opening. This ensures that the oil flowing into the lamellar chamber flows axially within the chamber due to the undercut deepening with axial distance from the outlet opening, thus guaranteeing that a particularly large number of the lamellae arranged in the lamellar chamber can be cooled by contact with the oil.Because the oil flows radially outwards in the radial direction as it is further away from the outlet opening in the axial direction due to the radial depression of the undercut, the oil is guided away from the outlet opening in the axial direction into the lamellar space due to centrifugal forces acting on the oil, especially along the lamellar pack.

[0022] In another possible embodiment of the invention, the outlet opening is arranged further rearward in the circumferential direction than the inlet opening. This allows the oil to flow particularly easily and reliably through the first oil supply channel from the inlet opening to the outlet opening, since inertial forces acting on the oil flowing into the first oil supply channel via the inlet opening can be used to guide the oil through the first oil supply channel. In other words, the oil flows into the first oil supply channel and the differential housing continues to rotate circumferentially while the oil is in the first oil supply channel.Because the differential housing moves in the circumferential direction and certain inertial forces act on the oil that has flowed into the first oil supply channel, the differential housing moves relative to the oil in the circumferential direction, or the oil arranged in the first oil supply channel moves relative to the differential housing in the opposite circumferential direction.

[0023] In a further possible embodiment of the invention, the differential housing has at least one oil draining channel with an oil draining inlet and an oil draining outlet, which are arranged circumferentially offset from the inlet of the first oil supply channel. This means that the oil draining outlet overlaps the inlet of the first oil supply channel over a circumferential axial length. The oil draining outlet and the inlet of the oil supply channel are spaced apart circumferentially. For example, the differential housing can have several first oil supply channels and several oil draining channels, with an inlet of the first oil supply channel and an oil draining outlet alternately arranged radially on the outer surface of the differential housing in the circumferential direction.The at least one oil removal channel enables defined oil removal from the lamellar space by directing oil away from the lamellar space via the at least one oil removal channel.

[0024] In this context, it can be specifically designed that the oil drain opening covers the lamellar assembly in a circumferential section of the lamellar assembly over its entire axial length. This means that in this circumferential section, the entire lamellar assembly is radially covered outwards by the oil drain opening, through which the oil can flow from the lamellar chamber into the oil drain channel. This ensures reliable oil removal from the lamellar chamber via the oil drain channel. By selecting a flow cross-section for the oil drain channel, for example by adjusting the circumferential length of the circumferential section, the volume flow rate of the oil flowing in the oil drain channel can be controlled.By adjusting this flow rate, the residence time of the oil in the lamellar chamber can be controlled before it flows out through the drain channel. The oil residence time in the lamellar chamber also controls the cooling of the lamellar assembly. Because the drain inlet extends along the entire axial length of the lamellar assembly, the risk of oil pooling—where oil accumulates and remains permanently trapped—is significantly reduced. This minimizes the formation of dead zones where oil can collect and not drain.

[0025] In a further possible embodiment of the invention, a nozzle of a pressurized oil line is directed towards the inlet opening of the first oil supply channel, allowing oil to be sprayed onto the inlet opening by means of the nozzle. The nozzle, and in particular at least a portion of the pressurized oil line, can be part of the limited-slip differential. The pressurized oil line is designed to supply pressurized oil, and thus pressurized oil, to the nozzle. The nozzle can direct the oil towards the inlet opening to ensure that a particularly large amount of the oil supplied by the nozzle flows into the first oil supply channel via the inlet opening.It is possible to use two nozzles. The first nozzle directs the oil towards the inlet of the first oil supply channel, while the second nozzle directs the oil towards a different inlet of the second oil supply channel. This ensures that oil flows into the finned space via the first oil supply channel and into the receiving chamber via the second oil supply channel. The first nozzle directs the oil towards the inlet of the first oil supply channel, resulting in a particularly high percentage of the directed oil jet actually entering the first oil supply channel through the inlet. This enables highly reliable and efficient cooling of the fins in the fin pack.

[0026] The invention further relates to a motor vehicle with a drivetrain comprising a locking differential, as already described in connection with the locking differential according to the invention. The drivetrain can, for example, be an electric drivetrain with an electric traction motor. The locking differential has a particularly small axial extent, which makes it particularly easy to integrate into the available installation space in the motor vehicle.

[0027] Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures themselves, can be used not only in the combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0028] The drawing shows in: Fig. 1. A schematic cross-section of a locking differential in a first embodiment for a motor vehicle, wherein the locking differential is shown cut along an axial direction parallel to a rotation axis of a differential housing of the locking differential; Fig. 2 a schematic sectional view of a section of the differential housing, wherein the differential housing is shown cut perpendicular to the axial direction; Fig. 3 a further schematic sectional view of the locking differential in a second embodiment, wherein the differential housing is shown cut perpendicular to the axial direction; Fig. 4 another schematic sectional view of the locking differential in a third embodiment, wherein the differential housing is shown cut perpendicular to the axial direction; Fig. 5 a further schematic sectional view of the locking differential in a fourth embodiment, wherein the differential housing is shown cut perpendicular to the axial direction; and Fig. 6 another schematic sectional view of the locking differential in a fifth embodiment, wherein the differential housing is shown cut perpendicular to the axial direction.

[0029] In the figures, identical and functionally equivalent elements are provided with the same reference symbols.

[0030] In Fig. Figure 1 shows a section of a limited-slip differential 10 for a motor vehicle in a cross-sectional view. The limited-slip differential 10 is designed as a differential gear with a differential lock 18. The limited-slip differential 10 comprises a differential housing 12, which is rotatable about an axis of rotation extending in the axial direction A during operation. The differential housing 12 defines a receiving space 14. Furthermore, the limited-slip differential 10 comprises two output gears 16, of which in Fig. Figure 1 shows only a partial representation. Each of the output gears 16 is connected to a driven wheel of the motor vehicle in a torque-transmitting manner. The output gears 16 are arranged within the receiving space 14 and are rotatable about the axis of rotation both relative to each other and relative to the differential housing 12. Furthermore, the locking differential 10 comprises at least one compensating gear arranged in the receiving space 14, which is not shown in the figures. This compensating gear is rotatably held on the differential housing 12 about a compensating axis of rotation that is fixed relative to the differential housing 12 by means of a compensating bolt 17 attached to the differential housing 12, the longitudinal extension of which runs in the radial direction. Fig. Figure 1 schematically indicates the compensating bolt 17 associated with the at least one compensating gear by means of a dashed line. The at least one compensating gear bears against each of the output gears 16. In particular, the compensating gear is toothed with each of the output gears 16, whereby a rotational movement of one of the output gears 16 can be transmitted to the other of the output gears 16 by means of the compensating gear, or a relative rotation of the output gears 16 can be compensated for.

[0031] The limited-slip differential 10 further comprises a differential lock 18, which includes a multi-plate clutch pack 20. The differential lock 18 is designed to be adjustable between a locked state and a unlocked state. In the locked state, the multi-plate clutch pack 20 connects the first of the output gears 16 to the differential housing 12 in a rotationally fixed manner. In the unlocked state, the multi-plate clutch pack 20 allows the first output gear 16 to rotate relative to the differential housing 12 about the axis of rotation. The multi-plate clutch pack 20 comprises a plurality of clutch plates 22, of which the first clutch plates 24 are rotationally fixed to the first output gear 16 and the second clutch plates 26 are rotationally fixed to the differential housing 12. For the sake of clarity, in Fig. 1. Only individual lamellae 22 are provided with the corresponding reference numeral. The first lamellae 24 and the second lamellae 26 are arranged alternately in the axial direction. The lamella assembly 20 is arranged in a lamella chamber 30, which in this case is bounded at least by the differential housing 12 and, in particular, additionally by the first output gear 16. The lamella assembly 20 further comprises a lamella assembly end disk 28, by means of which the lamella assembly 20 is closed off in the axial direction on the side facing the compensating bolt 17. Because the lamella assembly end disk 28 is arranged on the side of the lamella assembly 20 facing the at least one compensating bolt 17, the lamella assembly end disk 28 prevents the flow of oil 32 from the lamella chamber 30 into the receiving chamber 14.By preventing the flow of oil 32 from the lamellar chamber 30 into the receiving chamber 14 by means of the lamellar pack end disc 28, it is necessary for efficient cooling of the lamellae 22 of the lamellar pack 20 and the wheels arranged in the receiving chamber 14 that oil 32 is explicitly supplied to both the receiving chamber 14 and the lamellar chamber 30.

[0032] The differential lock 18 additionally comprises an actuating device which is designed to adjust the state of the clutch pack 20. The clutch pack 20 and the actuating device are arranged axially A on opposite sides of the at least one compensating bolt 17 of the locking differential 10. Furthermore, the clutch pack 20 radially overlaps the first output gear 16 outwards. It is also provided that the actuating device is designed to adjust the position of the clutch pack 20. Fig. 1. The second output gear (not shown) is radially overlapped on the outside. Due to this design, the Fig. The locking differential 10 shown in Figure 1 has a particularly small extent in the axial direction A and is therefore particularly compact in the axial direction A.

[0033] To explicitly supply oil 32 to the clutch chamber 30, the differential housing 12 has a first oil supply channel 34. To supply oil 32 to the receiving chamber 14, the differential housing 12 has a second oil supply channel 36. The limited-slip differential 10 can have at least one pressurized oil line with at least one, and in particular two, nozzles, each nozzle being directed towards one of the oil supply channels 34, 36. This means that pressurized oil from the pressurized oil line can be directed towards the first oil supply channel 34 by means of a first nozzle, in order to achieve an inflow of oil 32 into the first oil supply channel 34. The second nozzle is designed to direct an oil jet onto the second oil supply channel 36 in order to ensure that oil flows into the second oil supply channel 36 and through the second oil supply channel 36 into the receiving chamber 14.

[0034] In Fig. 2 is the differential housing 12 partially transverse to the axial direction A, which in Fig. 2 extending into the image plane, shown in section. Here, the differential housing 12 is shown in section in the area of ​​the first oil supply channel 34. The first oil supply channel 34 has an inlet opening 38 and an outlet opening 40. The inlet opening 38 is located radially further outwards than the outlet opening 40. The outlet opening 40 opens into the lamellar chamber 30. The in Fig. 2 The sectional view of the differential housing 12 shown corresponds to a section of the differential housing 12 along the line marked A:A in Fig. 1. To ensure particularly precise and reliable guidance of the oil 32 via the first oil supply channel 34 into the lamellar chamber 30, it is provided that the oil 32 is sheared off by means of a first inlet opening edge 42, which limits the inlet opening 38 in the circumferential direction U to the rear, when the differential housing 12 is rotated about the axis of rotation in the circumferential direction U. For this purpose, the first inlet opening edge 42 is, as in Fig. 2 can be particularly well identified by walls that taper at an acute angle. The inlet opening edge 42 thus has a cross-section running perpendicular to the axial direction A, as shown in Fig. As shown in Figure 2, the first inlet opening edge 42 is formed at a sharp angle, whereby the oil 32, directed towards the inlet opening 38 in the form of an oil jet, can be scooped or planed into the first oil supply channel 34 by means of this first inlet opening edge 42. Thus, as shown in Figure 2, the oil can be directed into the first oil supply channel 34. Fig. As can be seen particularly well, the outlet opening 40 is arranged offset to the rear in relation to the circumferential direction U compared to the inlet opening 38. The inlet opening edge 42 can be, as in Fig. As indicated by the dashed line 78, the inlet opening edge 42 runs obliquely rather than parallel to the axial direction A. In a top view, it can thus be seen that the inlet opening edge 42 runs obliquely to the axial direction. This means that the inlet opening edge 42 projects to different degrees in the circumferential direction U in different length sections arranged side by side in the axial direction A. The inlet opening edge 42 can, for example, be straight.

[0035] In the present case, it is the case that in Fig. In the first embodiment shown in Figure 1, it is further provided that a first outlet opening edge 44 of the differential housing 12, which limits the outlet opening 40 towards the compensating bolt 17, has a greater distance in axial direction A to the compensating bolt 17 than a second inlet opening edge 46, which limits the inlet opening 38 towards the compensating bolt 17. Furthermore, it is provided in the present case that a second outlet opening edge 48, which limits the outlet opening 40 and is opposite the first outlet opening edge 44 in axial direction A, has a greater distance in axial direction A to the compensating bolt 17 than a third inlet opening edge 50 of the differential housing 12, which limits the inlet opening 38 in the axial direction away from the compensating bolt 17.The first oil supply channel 34 thus extends from the inlet opening 38 to the outlet opening 40 along the axial direction A away from the compensating bolt 17 and in the radial direction R from the outside to the inside, and thus in the direction of the axis of rotation of the differential housing 12. To prevent the oil 32 from being flung out of the clutch chamber 30 as a result of impacting the clutch pack 20 against the direction of oil flow through the first oil supply channel 34, the clutch chamber 30 is designed to form a radial undercut 52 towards the outlet opening 40. This allows the oil 32 to collect in this undercut 52 during operation and form an oil pool 54. Individual, and in particular several, of the clutch plates 22, especially the second clutch plates 26, can project into this oil pool 54. This allows the fins 22, which project into the oil reservoir 54, to be cooled particularly efficiently by means of the oil 32. As in . Fig. 1. In order to be particularly well recognized, it is provided here that the undercut 52 deepens in the radial direction R with increasing axial distance A from the outlet opening 40.

[0036] As in Fig. As can be seen particularly well in Figure 2, the outlet opening 40 is arranged further back in the circumferential direction U than the inlet opening 38. This means that a fourth inlet opening edge 56 of the differential housing 12, which limits the inlet opening 38 forward in the circumferential direction U, is arranged in the circumferential direction U in front of a third outlet opening edge 58, which limits the outlet opening 40 forward in the circumferential direction U.

[0037] To allow the oil 32 to flow out of the lamellar chamber 30, the locking differential 10, in particular the differential housing 12, is provided to have at least one oil drain channel 60. As shown in Fig. To ensure that the oil drain channel 60 can be particularly well identified, it is provided that the drain channel 60 partially overlaps the first oil supply channel 34 in the circumferential direction U to the rear. The oil 32 can thus flow into the lamellar chamber 30 via the first oil supply channel 34, flow through the lamellar chamber 30, and flow out of the lamellar chamber 30 through the drain channel 60, in particular out of the differential housing 12. Because the drain channel 60 is arranged behind the first oil supply channel 34 in the circumferential direction U, it is offset relative to the first oil supply channel 34 in the circumferential direction U. The drain channel 60 has a drain inlet opening 62 and a drain outlet opening 64. The drain inlet opening 62 limits the drain channel 60 towards the lamellar chamber 30. Fig. 1 The oil draining channel 60 is indicated by dashed lines 66. As in Fig. To ensure that the oil drain inlet opening 62 can be clearly seen, it is provided here that the lamellar assembly 20 covers the lamellar assembly 20 in a circumferential section U extending along the entire axial length A of the lamellar assembly 20. This ensures that all oil 32 flowing into the lamellar chamber 30 via the at least one oil supply channel 34 can be discharged from the lamellar chamber 30 via the at least one drain channel 60. Within the lamellar chamber 30, the oil 32 can be carried along by the lamellar 22 in the circumferential direction U.

[0038] At the in Fig. In the second embodiment shown in Figure 3, it is provided that at least some of the lamellae 22, and in particular at least some, and in particular all, of the first lamellae 24 have a radially outer indentation or recess 68, whereby a distribution channel 70 is formed by the recesses 68 of several of the lamellae 22. The distribution channel 70 extends at least partially along the axial direction A, in particular parallel to the axial direction A. Alternatively, the distribution channel 70 can extend obliquely to the axial direction A. By means of this distribution channel 70, oil 32 flowing along the lamellae 22 can be distributed in the axial direction to ensure that the oil 32 reaches all lamellae 22.This is particularly advantageous if the first oil supply channel 34 runs with its longitudinal extension direction perpendicular to the axial direction A, and thus the oil 32 flowing in the first oil supply channel 34 flows only in the radial direction R and in the circumferential direction U towards the lamellae 22. In particular, at least the first lamellae 24, as in the . Fig. 3, Fig. 4 to Fig. 5 can be particularly well identified by having several tabs projecting radially in the direction R. The respective recesses 68 are arranged in particular on the respective tabs.

[0039] At the in Fig. In the embodiment shown in Figure 4, the first inlet opening edge 42, which limits the inlet opening 38 in the circumferential direction U to the rear, is provided by a planing element 72. In this case, this planing element 72 is a plate which is inserted into a recess of the differential housing 12.

[0040] This means that the planing element 72 does not protrude beyond the differential housing 12, but rather is flush with the differential housing 12 radially outwards. As shown in the enlarged section in Fig. Since the contour of the area of ​​the planing element 72 providing the first inlet opening edge 42 can be particularly well identified, it can be freely chosen. In this case, a planing edge 74 providing the first inlet opening edge 42 is curved with its axial course around the radial direction R. The planing element 72 can also be curved around the radial direction R or be straight in the circumferential direction.

[0041] At the in Fig. In the embodiment shown in Figure 5, the first inlet opening edge 42, which limits the inlet opening 38 in the circumferential direction U to the rear, is provided by a vane element 76. This vane element 76 can be bonded radially to the outside of the differential housing 12. By means of the vane element 76, a particularly large amount of oil 32 can be scooped from an oil jet directed towards the inlet opening 38 into the first oil supply channel 34.

[0042] At the in Fig. In the embodiment shown in Figure 6, a front surface of the lamellae 22 of the lamella pack is flat. This surface runs parallel to the flow direction in which the oil 32 flows within the first oil supply channel 34. For clarity, in Fig. 6 only individual lamellae 22 of the lamella package 20 are explicitly shown. As in Fig. As can be further identified in section 6, it is provided that the oil 32 is guided radially inwards through the differential housing 12 in a first section 80 of an oil path. The first section 80 is provided, at least partially, by the first oil supply channel 34. In a second section 82 of the oil path, adjoining the first section 80 in the circumferential direction U, the oil 32 is guided radially outwards between lamellae 22 arranged side by side in the axial direction A. In the second section 82, the radial height of the lamellae 22 increases with increasing distance from the first section 80 in the circumferential direction U. This radial design of the lamellae 22, combined with centrifugal forces acting on the oil 32, assists the oil 32, which is guided between the lamellae 22, in flowing circumferentially through the oil path.

[0043] In a limited-slip differential 10 with active lubrication, both the gears of the differential and the clutch pack 20 must be lubricated. Active oil injection into the limited-slip differential 10 is used to lubricate and cool the gears of the limited-slip differential 10 from the outside. Furthermore, the clutch pack 20 must be lubricated and cooled.

[0044] In order to achieve the smallest possible installation space requirement for the locking differential 10, it is necessary to use the following in Fig.Figure 1 shows a locking differential 10 in which a transverse lock is integrated into the gearbox of the electric drive motor. This results in a particularly small axial dimension available for the locking differential 10. By directly integrating the locking differential 10 into the gearbox of the electric drive motor, the gearbox oil of the electric drive motor can be used to lubricate and cool the locking differential 10. Oil 32 with a low temperature limit can be used for this purpose. It is essential to prevent the clutch pack 20 from overheating by actively cooling it with the oil 32, as this could cause the locking differential 10 or the gearbox to overheat and potentially lead to gearbox failure. Simultaneously, lubrication of the gears of the locking differential 10 must also be ensured.The oil injection velocity of the oil 32 into the first oil supply channel 34 is significantly lower than the maximum circumferential speed of the differential housing 12. It must be ensured that a required quantity of oil reaches the clutch plates 22 while simultaneously preventing the oil 32 from being flung off the plates 22 due to centrifugal force acting upon it. To meet these requirements, the oil 32 is supplied to the clutch plates 22 located in the clutch chamber 30 via the first oil supply channel 34. The use of two nozzles allows for a defined distribution of the oil 32 supplied by a pressurized oil line.For example, 70% of the supplied oil 32 can be fed into the clutch chamber 30 via the first oil supply channel 34, and 30% of the oil 32 supplied via the pressure oil line can be fed to the wheels of the limited-slip differential 10 arranged in the receiving chamber 14 via the second oil supply channel 36. Through the two oil supply channels 34, 36 with their individual guide geometries of the differential housing 12, a respective oil jet can be individually supplied to or discharged from the component to be lubricated, and thus to the clutch pack 20 or the wheels arranged in the receiving chamber 14.

[0045] Defined slopes in the walls of the differential housing 12, which bound the first oil supply channel 34, guide the oil 32 in all three spatial directions and prevent it from escaping through the inlet opening 38 of the differential housing 12. This prevents the oil 32 from being flung off the clutch pack 20 in an uncontrolled manner. When the oil jet reaches the clutch pack 20, a tipping point can be reached at defined flow velocities. At this point, the centrifugal force acting on the oil 32 outweighs the input impulse of the pressurized oil from the pressurized oil line. If the oil 32 strikes the clutch pack 20 in axial direction A at the level of the tipping point, it would flow directly radially outwards.Therefore, by providing the undercut 52, the tipping point is geometrically set such that, upon reaching the tipping point, the oil 32 flows into the undercut 52 instead of flowing radially outwards from the differential housing 12. While the oil 32 flows in the undercut 52, it has time to dissipate heat from the clutch plates 22 and exert its lubricating effect until it can flow out of the clutch plate space 30 through the defined, at least one, draining channel 60, in particular by being flung off. The three chamfers of the walls of the differential housing 12 that bound the first oil supply channel 34 allow the oil 32 to be radially skimmed as it flows into the first oil supply channel 34 via the inlet opening 38, thus eliminating the centrifugal force acting on the oil 32 and guiding it axially in direction A into the clutch plate space 30.Further inclined surfaces of the walls of the differential housing 12, which define the first oil supply channel 34, accelerate the oil 32 in axial direction A and ensure axial delivery of the oil 32 beyond the tipping point into the lamellar chamber 30. The tipping point is defined by the second outlet opening edge 48.

[0046] To protect the oil 32 from overheating and damage, at least one defined oil drain channel 60 is provided. A path for the oil 32 through the differential housing 12 is thus defined entirely by means of the first oil supply channel 34, the clutch chamber 30, and the at least one oil drain channel 60. This allows the oil 32 to be optimally guided through the limited-slip differential 10. By varying the diameters of individual clutch plates 22 of the clutch pack 20, a particularly large wetting surface area of ​​the clutch pack 20 can be created, thereby enabling particularly efficient cooling of the clutch pack 20. In particular, it is provided that the housing-fixed second clutch plates 26 project into the oil reservoir 54. It is also possible for the first clutch plates 24, which are rotationally fixed to the first output gear 16, to project into the oil reservoir 54.However, there may be a conflict of objectives between having the largest possible total surface area of ​​the lamellar package 20 and the deepest possible immersion of the first lamellars 24 attached to the first output wheel 16 into the oil collection 54.

[0047] Overall, the invention shows how the lubrication of a differential lock 18 in an electric drive can be implemented. Reference symbol list 10 Locking differential 12 Differential housings 14 Recording room 16 first output gear 17 compensating bolts 18 Differential lock 20 slat package 22 slats 24 first slats 26 second slats 28 lamellar pack end disc 30 slat space 32 Oil 34 first oil supply channel 36 second oil supply channel 38 Inlet opening 40 Outlet opening 42 first inlet opening edge 44 first outlet opening edge 46 second inlet opening edge 48 second outlet opening edge 50 third inlet opening edge 52 Undercut 54 Oil accumulation 56 fourth inlet opening edge 58 third outlet opening edge 60 Oil drain channel 62 Oil drain inlet opening 64 Oil drain opening 66 dashed lines 68 Exclusion 70 distribution channel 72 Planing element 74 Planed edge 76 shovel element 78 dashed line 80 first section of the Oil Route 82 second section of the Oil Route A axial direction R radial direction U circumferential direction

Claims

[1] Locking differential (10) for a motor vehicle, with - a driveable differential housing (12) rotatable about a pivot axis, which encloses a receiving space (14), - two output gears (16) which are rotatable relative to each other about the axis of rotation, which are arranged within the receiving space (14) and are rotatable relative to the differential housing (12), - at least one compensating gear arranged in the receiving space (14), which is rotatably held on the differential housing (12) by means of a compensating bolt (17) attached to the differential housing (12) about a compensating axis of rotation fixed to the differential housing (12), which rests against each of the output gears (16) and is designed to transmit a rotational movement of one of the output gears (16) to the other of the output gears or to compensate for a relative rotation of the output gears (16) to each other, and - a differential lock (18) comprising a multi-plate clutch (20), which is designed to be adjusted at least between a locking state in which a first of the output gears (16) is rotationally fixed to the differential housing (12) and a release state in which the multi-plate clutch (20) allows a relative rotation of the first output gear (16) to the differential housing (12), wherein - the lamellar package (20) and an actuating device, which is designed to adjust the state of the lamellar package (20), are arranged on axially opposite sides (A) of the compensating bolt (17) each radially overlapping one of the compensating wheels, whereby the lamellar package (20) is fluidically separated from the receiving space (14) by means of a lamellar package end disk (28), - the differential housing (12) has at least one first oil supply channel (34) with an inlet opening (38) and an outlet opening (40) by means of which oil (32) can be supplied to the clutch pack (20), and has at least one second oil supply channel (36) by means of which oil (32) can be supplied to the receiving chamber (14), and - the locking differential (10) is designed such that the oil (32) is guided radially inwards in a first section (80) of an oil path extending in the circumferential direction (U) through the differential housing (12) and in a second section (82) of the oil path adjoining the first section (80) in the circumferential direction (U) the oil (32) is guided radially outwards between lamellae (22) arranged next to each other in the axial direction (A). [2] Locking differential (10) according to claim 1, characterized by, that an edge (42) of the differential housing (12) limiting the inlet opening (38) of the first oil supply channel (34) in the direction of rotation (U) of the differential housing (12) to the rear about the axis of rotation is formed with an angle tapering to a point in the cross-section perpendicular to the axial direction (A), whereby oil (32) of an oil jet directed towards the inlet opening (38) can be scooped into the first oil supply channel (34) by means of this edge (42). [3] Locking differential (10) according to claim 1, characterized by , that an edge (42) limiting the inlet opening (38) of the first oil supply channel (34) in the direction of rotation (U) of the differential housing (12) about the axis of rotation is provided by a plate-shaped planing element (72) or a scoop-shaped blade element (76) attached to the differential housing (12). [4] Locking differential (10) according to any one of the preceding claims, characterized by , that the lamellar package (20) has a distribution channel (70) which is formed by recesses (68) in several lamellae (22) of the lamellar package (20), wherein the distribution channel (70) extends at least partially in the axial direction (A) with its longitudinal direction, whereby oil (32) which has flowed to the lamellar package (20) can be guided and / or distributed in the axial direction (A) by means of the distribution channel. [5] Locking differential (10) according to any one of the preceding claims, characterized by , that the outlet opening (40) opens into a lamellar space (30) in which the lamellar package (20) is arranged, wherein - a first edge (44) of the differential housing (12) limiting the outlet opening (40) towards the compensating bolt (17) has a greater distance in axial direction (A) to the compensating bolt (17) than an edge (46) of the differential housing (12) limiting the inlet opening (38) towards the compensating bolt (17), and / or - a second edge (48) limiting the outlet opening (40) and opposite the first edge (44) in the axial direction (A) has a greater distance in the axial direction (A) to the compensating bolt (17) than an edge (50) of the differential housing (12) limiting the inlet opening (38) in the axial direction (A) towards the side facing away from the compensating bolt (17), whereby oil (32) guided in the first oil supply channel (34) is guided axially towards the end disk of the clutch pack (28). [6] Locking differential (10) according to claim 5, characterized by , that the lamellar space (30) forms a radial undercut (52) to the outlet opening (40), which allows the oil (32) to collect in the undercut (52). [7] Locking differential (10) according to claim 6, characterized by , that the undercut (52) deepens in the radial direction (R) with increasing axial distance from the outlet opening (40). [8] Locking differential (10) according to any of the preceding claims, characterized by , that the outlet opening (40) is located further back in the circumferential direction (U) than the inlet opening (38). [9] Locking differential (10) according to any one of the preceding claims, characterized by , that the differential housing (12) has at least one oil draining channel (60) with an oil draining inlet opening (62) and an oil draining outlet opening (64) which is arranged offset in the circumferential direction (U) to the inlet opening (38) of the first oil supply channel (34). [10] Locking differential (10) according to claim 9, characterized by , that the de-oiling inlet opening (62) covers the lamellar pack (20) in a circumferential section of the lamellar pack (20) over an entire length of the lamellar pack (20) extending in the axial direction (A). [11] Locking differential (10) according to any of the preceding claims, characterized by, that a nozzle of a pressure oil line is aligned with the inlet opening (38) of the first oil supply channel (34), whereby oil (32) can be sprayed onto the inlet opening (38) by means of the nozzle. [12] Motor vehicle with a drive train comprising a locking differential (10) according to any of the preceding claims.

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